Furnace.



- W. McCLAVE.

Patented Aug. 1, 1916.

2 SHEETS-SHEET I.

W. McCLAVE.

FURNACE. APPLICATION FILED DEC- I9. I914.

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' mechanism by an arrangement of dead plates In furnaces of a; Tm) srn'rns PATENT orriC WILLIAM MGCLAVE, OF SCRANTON, PENNSYLVANIA, ASSIGNOR TO MGCLAVE-BROOKS COMPANY, OF SCBANTON, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

V FURNACE.

Specification of LettersPatent.

Application filed December 19, 1914. Serial No. 878,171.

To all whom it may concern.-

Be it known that I, WILLIAM MoCLAvE, a citizen of the United States, residing at Scranton, in the county of Lackawanna and State of Pennsylvania, have invented a certain new and useful Improvement in Furnaces; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification, and to the figures and letters of reference marked thereon.

This invention relates to steam boiler furnaces and particularly to furnaces wherein the stoking means and grate construction are adapted to handle and utilize low grade fuels such as buckwheat, birdseye, slack, etc.

The objects of the invention are the production of a highly efficient furnace in which the arrangement of the fuel feeding mechanism and its necessary elements will permit of an unobstructed view of the grate bars and enable the operator to manipulate the burning fuel with slice bars, pokers, etc., without disarrangement or interference with the mechanical stoking means.

Another object of my invention is to provide a fuel pusher of comparatively small vertical dimension, whereby fuel fed thereby is directed at a point near the top faces of the grate bars supporting the burning coal, giving as near as may be an underfeed rather than an overfeed operation in the supply of unburned coal.

Another object is to maintain a'low temperature of the castings adjacent the feeding and cooling ports therein. the class under discussion, very high 'tem-' peratures are maintained in the combustion chambers and are communicated by conduction to the metallic parts nearby and it is of the utmost importance to the prolonged life of such parts that they be protected from the disintegrating action of the intense heat.

These and other novel features and improvements contained in the present structure will be hereafter more fully set forth.

In the drawings,-Figure 1 isa longitudie nail vertical section of the furnace. Fig. 2 1s a cross section taken on line BB of Fig. 1. Fig. 3 is a horizontal cross section taken through the upper edge of the upper dead plate on line AA.

Similar letters of reference in the several figures indicate the same parts.

Furnaces of the type to which this invention is applied are utilized, generally speaking, for heating boilers, with bituminous coal, but may also be used for burning some other kinds of coal fuels. It is so designed that the fuel may be either mechanically fed onto the grate bars or by hand tools when so required, and with uniform distribution of same, either method requiring but little power, as the angle of the grate isbut slightly less than the angle of rest of the fuel, which permits gravity to do a part of the work.

As the maximum efficiency from a furnace resides largely in the degree of care exercised by the operator, in manipulating the feed and keeping the, fire free from clinker, ash, etc., and regulating the air supply, it is of great importance that the arrangement of doors be such that the whole surface of the fire bed be readily observed. Thus in the present invention, the furnace door is so located with respect to the grate and the stoking mechanism as to open up the whole fire bed to the eye of the operator and at the same time not materially interfere with the stoking mechanism.

The top of the furnace illustrated in the accompanying drawings, is formed by the arch A with the openings a for the entry of preheated 'air from the preheating chamber B. The grate C lies in an inclined position with respect to the arch A and has an angular relation nearly equivalent to the limit of thean'gle of 'rest of the material used as fuel. In the same plane as the grate C- a dead plate D is provided, upon which the incoming fuel is received, and mounted thereonis a' fuel pusher d connected with means for reciprocating the pusher, there being in usual practice two or more of such pushers in each furnace. Said pusher d is housed by the; lower dead plate D and an upper dead plate E which is bolted to the front wall 6 of the furnace. The upper dead plate E is provided with a fiat portion 1 which constitutes the top housing of the pusher (Z and has a series of comparatively widely spaced ribs 2 which project into and across the fuel chute 3, leading from the hopper l. The ribs 2 of the upper dead plate extending across said chute 3, terminate in a hollow transverse air conduit G which forms the sill of the door 7 The ribs 2 extending across the path of the incoming fuel serve also to break up and grade the fuel so that a more nearly uniform coal is delivered by the pushers to the grate. The air conduit G extends transversely across the entire furnace and is connected by pipes through the side walls of the furnace with means for regulating and controlling the passage of the air therethrough.

The air circulating system, see Fig. 2, consists in part of downwardly extending air pipes 5 and 6, located mainly in the side walls of the furnace, the pipes opening at the lower ends in the ashpit at points 7 and 8. Located at one side of the air conduit G and without the side wall of the furnace is provided a steam jet blower 9 Whose nozzle projects into the air pipe 5 in the direction of opposite branch 6. On the opposite side from the jet blower 9 the air conduit G is connected to the downwardly extending branch 6 by a valve 10, which has threaded into its upper end pipe 11 which extends into the preheating chamber B. At the center of the air conduit G a downwardly extending cooling pipe I is provided, which serves a dual purpose, first, as a supporting means for the conduit, and secondly, as an outlet of air into the ashpit. This cooling pipe I is supported on the lower dead plate D and extends therethrough at a point 12. It should be borne in mind that the main purpose of driving air through the conduit G is to keep the front edge of the upper dead plate and the surrounding parts cool, but the heat abstracted from the conduit is an im portant factor in raising the temperature of the air being supplied through the arch of the furnace to burn the gases. The single jet blower 9, which in practice is found to be efficient with a nozzle of about 3/32 of an inch in diameter, is constantly in use, except when the fire is banked, or when it is not very hot.

In Fig. 1, the ordinary blast pipe 13 is shown, as is customary in furnaces of this class. As will be readily understood, the blast from this pipe entering the ashpit will force nearly air enough up through the branches 5-6 of the air tube to supply through the conduit G, and thence up through pipe 11, to the preheating chamber and through the perforations a in the arch A to burn the gases, etc., over thefire, yet there are times, when the blast is shut off from the ashpit, that render the jet blower of extreme importance as a means of alone impelling the air current.

The valve 10, located at the junction of the branch pipe 6 with conduit G, is provided with a fiat blade 1 f pivotally arranged so that the swinging of the blade directs the air current either to the arch of the furnace, or to the ashpit, as may be required, or, in fact, the current may be divided, part going to the arch outlets and the other part to the ashpit. The air current traversing the conduit G necessarily abstracts heat there-from and that heat is utilized in burning the gases when it goes to the arch outlets. When the heated air is directed to the ashpit it also raises the temperature there to a more ellicient degree. The hopper 4 is located above the dead plates E and D and at its outer lower edge is provided with a swinging door K, which door in its normally closed position, abuts the upper dead plate E at 0. Approximately opposite the swinging door K is located the furnace door 7 As is shown in Fig. 3, the furnace door is journaled in the frame of the furnace at points 18-49 and is constructed of a metallic back plate 0 on which is secured a thick outwardly curving face of fire brick O. The lower edge of the inner wall of hopper 4 is cut away at L in an inwardly curving manner and the lower part of arch A adjacent to the curved portion L of the hopper wall is also cut away from point L to L \Vhen in closed position the furnace door is partly housed in the curved part of the hopper wall and its arch A. The conduit G of the upper dead plate E forms the sill of said revolving door. The furnace door 7 is provided with a lever M for manually controlling its movement. In Fig. 1 the swinging door K is shown in closed position so that this door is, in effect, one wall of the chute for fuel, with the furnace door forming the other wall. hen it is desired to observe the grate or manipulate with hand tools the surface of the grate, the door 7 is revolved and owing to its location, cuts off the delivery of fuel from the hopper to the stoking means. The swinging door K is then opened and the fireman is enabled to see the entire surface of the fire bed. The closing of the furnace door will drive the fuel before it, pushing part of any fuel that has collected over the front edge of the upper dead plate, and part of it between the ribs through under the cooling tube or air conduit onto the lower dead plate.

The operation of the furnace, from the forego'mg description, is easily understood.

The fuel is deposited in the hopper and enga e-' mension, the fuel is in effect fed to the bottom of thefire bed in the nature of an underfeed delivery, without the radical changes in construction that distinguish the underfeed type of furnace stoking from the ordinary overfeed.

What is claimed is:

1. In a furnace of the class described, the combination of a hopper, an inclined grate, a dead-plate lying in a substantially coincident plane, an upper dead-plate provided with fuel openings therethrough located in the path of the fuel supply, a pusher between said dead-plates, means for reciprocating said pusher, a fuel chute between the hopper and upper dead-plate, a swing ing door hinged to said hopper forming one wall of the chute and a furnace door forming the other wall of said chute, the furnace door directing the flow of fuel to the openings in the upper dead-plate 2. In a furnace of the class described, the combination with a hopper, an inclined grate, a dead-plate lying in the same plane as the grate, a chute connecting said hopper with the dead-plate, an upper dead plate comprising a fiat inclined portion at its outer side, a series of ribs extending inwardly therefrom across said chute and terminating in a transverse inner edge, a pusher lying between the dead-plates, and means for reciprocating said pusher.

3. In a furnace of the class described, the combination with a hopper, an inclined grate, a dead-plate lying substantially in the same plane as the grate, a chute between the hopper and dead-plate, whose side walls are formed by an outer hinged door and an inner furnace door, an upper dead-plate consisting of a fiat inclined surface at the outer side and a series of ribs extending inwardly across the chute, said dead-plate being provided at its inner edge with a hollow air conduit, a pusher lying between said deadplates, and means for reciprocating said pusher.

4. In a furnace of the class described, a feeding device comprising a hopper, a deadplate lying substantially in the same plane as the grate, an upper dead plate provided with a plurality of openings for the passage of fuel, an air conduit integral with and forming the inner edge of said dead-plate, a downwardly extending air pipe connected to said air conduit extending into the firebox, pusher mounted between the dead plates anduneans forreciprocating same, and'an'inclined grate adapted to receive the advanced fuel. i

15;Ina furnace of the class, described, a, feeding device comprising ahopper, a lower dead plate lying in inclined position thereto, 'an upper dead plate provided with a plurality of openings for the passage of fuel, an air conduit forming theinner edge of. said dead plate and an air supply pipe connected therewith, passing through said lower dead plate into the fire box, a pusher mounted between the dead plates and means for reciprocating same, an inclined grate adapted to receive the advanced fuel.

6. In a furnace of the class described, a hopper, an inclined grate surface, a dead plate lying in a coincident plane, a pusher mounted on said dead plate, an upper dead plate partly housing said pusher, an air conduit located in the inner edge of the upper dead plate, pipes connected with the air conduit extending downwardly into the ash pit, means for regulating the circulation of air through said pipes, a preheating chamber, and a connection between said air conduit and said preheating chamber, substantially as described.

7. In a furnace of the class described, the combination of an upper and lower dead plate and an inclined grate lying in substantially the same plane as said dead plates, said upper dead plate having an air conduit at its inner edge, pipe connections extending downwardly from said air conduit on either side of the inclined grate, projecting into the fire box, substantially as described.

8. In a furnace of the class described, a hopper, an inclined grate, dead plates intermediate the hopper and grate, a fuel chute connecting said hopper and dead plates whose outer wall is formed by a door hinged to said hopper and whose inner wall is formed by a revolving furnace door, said furnace door when open to the grate automatically cutting off connection between the hopper and fuel chute.

9. In a furnace of the class described having an arched top portion, the combination of an inclined grate, a lower dead plate lying in a coincident plane, a pusher mounted on said dead-plate, an upper dead-plate extending over the pusher, fuel openings in the upper dead-plate, a transversely ar ranged air conduit integral with and forming the inner edge of said dead-plate, a fuel discharge formed between the air conduit and the lower dead-plate, and a furnace door mounted between the air conduit and the arch of the furnace.

10. In a furnace of the class described, a hopper, an inclined grate, a lower deadplate lying in a coincident plane, a swing ing door mounted on the outer hopper wall, the air conduit, whereby access to the grate an upper dead-plate provided with an outer bars may be had Without regard to the po- 19 fiat portion and an inwardly extending persition of the furnace door.

forate portion terminatin in an air con- 7 duit, a revoluble furnac e door mounted WVILLIAM MCCLA above the air conduit, said air conduit constituting a sill therefor, a fuel discharge opening between the lower dead plate and Witnesses:

C. A. KEEGAN, JAMES A. MGCORMAOK.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

